[rfc-i] DOIs and RFCs

One thing to bear in mind about DOIs is that if you do it for new RFCs, authors of old RFCs might clamor to be included as well. Whether we should honor their requests on a case-by-case basis, just proactively get DOIs for all RFCs, refuse to honor such requests, or some other alternative is open to debate, of course, but we ought to have that on the list of issues to address if we decide to apply for DOIs for new documents.